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SILENCER SHEETSdesCRiPtion

Vibro-Acoustics RLP and CLP silencers have 100% of

the glass fiber or expansion chambers outboard of theairstream. By allowing the silencer outboard dimensions toexceed the duct cross section dimensions, and maintaininginternal dimensions equal to the connecting ductdimensions, RLP and CLP silencers will have a pressure dropalmost equal to empty duct. The difference is only the roughness factor of perforated metal over solid.RLP and CLP silencers can be straight or also include bendsand transitions. The most common thickness of acoustictreatment is 4 for noise control. Thicker treatment of 6 oreven 8 is more effective in the low frequency range. It isusually applied to all four walls. For higher duct aspectratios, application to the larger two walls could suffice.RLP-D and CLP-D silencers use acoustic grade glass fiberprotected by perforated metal. The thick mediaprovides excellent attenuation if sufficient length isavailable at virtually no pressure drop. Glass fiber clothin addition to the perforated metal prevents glass fibererosion above 4000 fpm for straight ducts and 2000 fpm atelbows and other fittings.RLP-FL and CLP-FL silencers incorporate a film liner betweenthe perforated metal and the glass fiber.RLP-NM and CLP-NM silencers do not use glass fiber andare completely void of any fill material.

aPPLiCation high duct velocity systems (see SAS 7) when fan system can not tolerate too much pressuredrop (see SAS 8) systems with long duct runs when long term energy cost and initial incremental system cost is more important than initial silencing cost to save redesign of equipment room when standardsilencers can not fit the space where break-out or break-in noise is of concern

FeatuRes and BeneFits

fully external acoustical media allows very low pressure drops available in any cross-sectional dimensionsto fit-the-duct made in sections to fit ceiling space and canincorporate notch-outs to facilitate cross-over beams, pipes,ducts, etc. can be selected to suit the acoustic, space, or energy-

Cautions / When not to use

RLP and CLP siLenCeRs when there is absolutely no room outside the ductconnection size (e.g. tight shafts) when there is not enough duct length consider using FanSilencers (SS10 and SS11) or EX Model Silencers (SS8) when break-out noise is of prime concern RLP and CLPsilencers may be appropriate selections. They may requiremass/stiffness added to their outer casing (seeHTL Silencers (SS7))

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SILENCER SHEETSteStiNg

Vibro-Acoustics 4th generation aero-acoustic laboratory was

the first laboratory to be NVLAP accredited for the ASTM E477 silencer test code. NVLAP is administered by the U.S.Dept. of Commerce. See the Corporate/ Laboratory Section.